I'm having exactly the same problem. Yesterday I updated to Limewire 4.16.6, and I started downloading three movies. (So unlike retro's situation, they hadn't been In Progress between Limewire versions) Two of them finally got to 100%, and stopped. I read in the forums that I should restart Limewire (this has worked for me in the past as well) so I restarted the whole computer and when I reconnected to Limewire, the two that had frozen at 100% dropped down to 75% and 81%, respectively.
They have now been "downloading" at over 100Kb/s for the past hour, and the percent hasn't moved at all! The one that's at 75 sometimes moves up to 76, and then drops back down to 75 again.
I've tried re-searching the items, but to no avail.
BTW, I'm in Canada, not the UK. Anyone who has had this problem as well found a solution? Should I restart the downloads? Is it a problem with my computer/program or the actual files?

I tried downloading a song just now, and it worked fine. Maybe just these files?? But they work as movies when I preview them...